I cannot say that I'm sorry to see the three interdependent sliders go. I am a bit sorry to see the tax slider go, because I rather like the ability to increase my empire's income without directly reducing manufacturing and research, although since I feel that your actual approval rating had probably too little impact on you I cannot say that I'm extremely disappointed to see that approval and variable taxes are gone.
The issue with approval and the tax slider was more that it was fairly easy to maintain control of the senate, and as long as you had control of the senate there were no penalties for having less than perfect approval, unless you had a planet or two with such poor approval that they're on the verge of rebellion. This could have been corrected by making it so that tax changes had to be approved by the senate, that the penalties caused by losing control of the senate started to kick in before you completely lost control of the senate (but not at full force - so perhaps if Populists controlled 20% and War Party controlled 10% while your Federalists controlled 60%, with the other parties sharing the remainder, you might have 90% of your Federalist bonuses, a third of the Populist penalties, and an eighth of the War Party penalties), or things like that. I also think that the approval rating should have had some degree of memory associated with it - if I've just spent ten turns at 100% taxes and then I reduce them to 30%, my approval should probably jump a bit. But it shouldn't instantly jump all the way up to wherever I would have been had I spent the past 10 turns at 30% taxes instead of 100% taxes; I could also see having the approval dive to a point lower than its long-term expected point immediately when there's a tax increase, and then slowly go to its 'stable' value as turns go on, and for minor tax changes (be they increases or decreases) to have significant immediate impact on the approval rating. Having the forgetting factor for this be something that could be adjusted in the faction customization, or even just be dependent on the base faction, could also be an interesting way to differentiate factions. But this is all purely academic, since it seems that approval and adjustable tax rates are a thing of the past.
I have yet to read something I like more than simply production wheel Maybe that wheel does not turn but neither does a cheeze wheel.
Well, a cheese wheel could turn, if you wanted it to.